Sleep Disorders

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[edit] Sleep Disorders

William Pryse-Phillips

T. Jock Murray

Sleep is a normal, complex, cyclical physiologic state in which consciousness and activity are altered. It is composed of non-rapid eye movement (NREM) sleep (divided into stages 1, 2, 3, and 4, according to its depth) and rapid eye movement (REM) sleep, characterized by profound muscular relaxation and by alterations of blood pressure, pulse rate, respiration, and electroencephalographic activity when compared with wakefulness. Despite the muscle inactivity, there are repetitive darting eye movements. If awakened in this stage, the subject will recall a vivid dream.✢✢Despite tremendous advances in understanding the physiology of sleep, our interpretation of the meaning of dreams has not advanced since Joseph, son of Jacob, counseled the Pharaoh (Genesis, 41:25).

When falling asleep, a person without a sleep disorder passes from a state of alertness to drowsiness and then into stage 1 NREM sleep, characterized by muscle relaxation and the appearance on the electroencephalogram (EEG) of low-amplitude, fast-frequency waves. During this stage the patient often denies having been asleep if asked. As the patient falls deeper asleep, he or she enters stage 2 sleep, with spindles of 12 to 16 Hz waves on the EEG, and then in turn stages 3 and 4, which are characterized by higher amplitude slow waves, profound muscle relaxation, and difficulty in rousing the subject. A healthy young adult going to bed at night rapidly passes through drowsiness with mental fantasies into stages 1 and 2 and then into longer periods of stages 3 and 4 sleep. After about 90 minutes of NREM sleep, the first REM sleep episode occurs. This is usually associated with a dream lasting 5 to 10 minutes, but during the night four to five further REM periods occur, each becoming progressively longer as the night continues. After the first REM period the subject again drops down through the NREM sleep stages and oscillates about every 90 minutes between one type of sleep and the other. Infants spend much of their time in stages 3 or 4 sleep but half of their sleep is of REM type. By the age of 5, REM sleep takes up about one fourth of sleep time, which is comparable to a young adult pattern. Approximately 5% to 10% of sleep is in stage 1, 50% in stage 2, and 20% in stages 3 and 4. REM sleep decreases somewhat after age 50, as does the time spent in the deeper stages of NREM (slow wave) sleep.

The major disorders of sleep are classified as dyssomnias, parasomnias, and sleep disorders associated with medical psychiatric disorders.

[edit] DYSSOMNIAS

Dyssomnias are disorders associated with difficulty in initiating or maintaining sleep, or with excessive sleep.

Intrinsic sleep disorders are sleep disorders that either originate or develop within the body or arise from causes within the body, such as psychophysiologic and idiopathic insomnia, narcolepsy, recurrent idiopathic and posttraumatic hypersomnia, sleep apnea, central alveolar hypoventilation syndrome, periodic limb movement disorder, and restless legs syndrome.

Extrinsic sleep disorders are those caused by some other stimulus arising from outside the body. The more common are altitude insomnia, insufficient sleep syndrome, and various sleep disorders resulting from exposure to hypnotics, stimulants, alcohol, or toxins.

Circadian rhythm sleep disorders include those problems related to changes in sleep schedules (e.g., time-zone change, shift work), and will not be discussed here.

[edit] Insomnia

Insomnia is the classic disorder of initiating and maintaining sleep and is the most common sleep complaint. It is also one of the most common complaints patients bring to a primary care physician. Insomnia is the inability to get to sleep or stay asleep for the time expected by the individual and is only an abnormality when the patient complains about it, because a person who sleeps for only 3 hours a night may accept this as his or her normal pattern. Insomnia is only a symptom; during the interview the physician must search for the underlying cause. Because many physicians lack understanding of sleep physiology and of the drugs that affect sleep, insomnia is also commonly mismanaged.

In most cases of insomnia there is an underlying psychologic disturbance. Over 85% of insomniacs have one or more major pathologic scores on the Minnesota Multiphasic Personality Test (MMPI), particularly on the scales for depression, sociopathy, obsessive-compulsive features, and schizophrenia. It is common for patients to concentrate on their sleep disturbance and ignore or deny the underlying emotional problem. Poor sleepers have been found to spend less time in REM and more time in NREM sleep stages 1 and 2. They also have an increased heart rate, peripheral vasoconstriction, and a higher body temperature during sleep, suggesting a higher level of physiologic arousal, which demonstrates that their sleep is different not only in quantity but also in quality from that of persons without sleep disorders.

The management of insomnia consists of improving sleep hygiene and often the use of drugs for a limited period. Alcohol, nicotine, and caffeine should be eliminated, emotional or medical problems (especially those causing dyspnea or pain or affecting bladder or bowel function) treated, and the bedroom made conducive to sleeping by reducing noise and light. The patient should use the bedroom for sleep only; if not asleep after 15 minutes, he or she should get up and go to another room and read until tired. Watching television is not recommended because the light and content are arousing. The patient should rise at the same time each morning regardless of how little sleep there was the previous night. Sleep restriction therapy requires that subjects stay in bed only for as long as they usually sleep, although the time is increased by 15 minutes per week as sleep time increases.

When medications are needed, the lowest effective dose should be employed, and dosing should be intermittent—perhaps 3 to 4 nights per week. Discontinuation should be gradual. Geriatric patients need only about half the dose normally used for younger adults. The use of barbiturates is obsolete because in the long term they disturb sleep even further, cause excessive daytime sleepiness, and may lead to rebound effects on discontinuation. Tryptophan is a natural, if weak, sleep promoter; a hot malted drink is the best thing to take as a late-evening beverage. Melatonin has anecdotal evidence for use as a sleeping aid but few controlled clinical trial results support its use. Tricyclic drugs, such as amitriptyline, frequently work well in cheerful insomniacs, but may lead to atropinic effects and daytime sleepiness.

Flurazepam induces normal patterns of sleep but its long half-life (5 days) may lead to excessive daytime sleepiness. Other benzodiazepines, such as triazolam (Halcion), temazepam (Restoril), lorazepam (Ativan), and diazepam (Valium), are acceptable medications for insomnia, but all are best used intermittently because with many, active metabolites accumulate, a constant blood level is attained, and cognitive impairment, sleepiness by day, incoordination, and sometimes depression may result.

Triazolam (Halcion) has a short action and limited “hangover” effect, but its short half-life may lead to the patient waking during the night, and its rapid action causes some to have impaired memory for the period while they remain awake after taking it.

[edit] Idiopathic Hypersomnia

Idiopathic hypersomnia is an uncommon condition characterized by a periodic or chronic tendency to sleep deeply for prolonged periods and to take frequent naps. Unlike narcolepsy, the tendency to sleep in hypersomnia is not irresistible and the onset of sleep is slower.

Characteristically, these patients feel confused on awakening and have difficulty becoming completely alert (“sleep drunkenness”). Like the patients who describe themselves as poor sleepers, hypersomniacs show a sleep pattern suggesting a more aroused or lighter type of sleep. Fatigue, lethargy, and poor motor and intellectual performance by day result. In the chronic hypersomniac, attention must be paid to the psychologic mechanisms underlying the symptoms, particularly depression. Stimulant drugs such as methylphenidate may be effective, but tricyclic drugs are usually better. Amphetamines should be avoided.

[edit] Kleine-Levin Syndrome

Kleine-Levin syndrome is characterized by bulimia (a tendency to eat excessively), hypersexuality, and prolonged sleeping. The patients are usually young men who sleep excessively for a number of weeks, awakening only to eat voraciously any food put in front of them. They also have a tendency to act out sexually during this state. The disorder usually clears spontaneously after a few years.

[edit] Central Alveolar Hypoventilation Syndrome

Central alveolar hypoventilation syndrome (Pickwickian syndrome✢✢Named after the Fat Boy in Dickens' The Pickwick Papers, who was usually asleep.), a disorder of periodic ventilatory insufficiency caused by gross obesity, is characterized by chronic sleepiness and a tendency to fall asleep easily when at rest.

[edit] Sleep Apnea

Sleep apnea is a condition in which repetitive nocturnal apneic spells result in recurrent hypoxemia and sleep disruption. When 15 or more apneic episodes occur per hour of sleep, symptoms appear, including complaints of restless nocturnal sleep with attacks of choking and repeated awakenings, excessive daytime sleepiness, morning headaches, nocturia, and irritability. Clinically, the condition presents most often with snoring, abnormal sleep behavior, excessive daytime sleepiness, intellectual deterioration, personality change, morning headache, and sleep disturbances. It occurs in association with a wide range of primary neurologic diseases, most of which affect the brainstem or the brain in a diffuse manner. There are two major types of sleep apnea; in each, the clinical diagnosis is confirmed by polysomnographic monitoring.

In central sleep apnea syndrome all ventilatory movements cease during sleep because of prolonged pauses in the central brainstem motor output to the ventilatory muscles. There are frequent episodes of shallow or absent breathing during sleep, associated usually with gasps, grunts, or choking during sleep; frequent body movements; and cyanosis. The result of this reduced ventilatory effort is oxygen desaturation. Patients commonly complain of excessive sleepiness and associated headache, but are sometimes unaware of the underlying problem. Avoidance of sedative drugs, alcohol, steroids, and diuretics is helpful prophylaxis. Medroxyprogesterone acetate and aminophylline or caffeine may stimulate the respiratory centers, reducing the number of spells. If these treatments are ineffective, mechanical ventilatory assistance may be required during sleep; this may require phrenic nerve stimulation or positive pressure ventilation through a tracheostomy. Cervical cordotomy, Chiari malformation, kyphoscoliosis, bulbar polio, and brainstem infarct or tumor are other causes of central sleep-related apnea, which may be accompanied by disturbed sleep with abnormal movements, hypnagogic hallucinations, enuresis, and somnambulism.

In obstructive sleep apnea syndrome there are repetitive episodes of upper airway obstruction during sleep, usually with a reduction in blood oxygen saturation. In this form, the diaphragm and chest wall move with variations in intrathoracic pressure, but there is no air flow at the nose or mouth. The problem is usually due to collapse of the muscular wall of the pharynx and less commonly to facial/palatal malformations or upper airway disease. Patients are commonly unaware of the apneic spells and of the “snorting and/or snoring” that signals the beginning of the respiratory phase, so a history from the bed partner is needed to confirm suspicions.

Many patients with sleep apnea are obese males who smoke and drink alcohol excessively. Their usual complaints are of excessive daytime sleepiness; morning headaches and a dry mouth on awakening; personality change, especially irritability; and some cognitive alteration. Milder cases of the condition may respond to losing weight, stopping smoking and drinking, and to the drug protriptyline. In more severe cases, because of the respiratory obstruction during sleep, surgical reconstruction of the pharynx (uvulopalatopharyngoplasty) may be needed. A permanent tracheostomy was once used in some cases, but nasal continuous positive airway pressure (CPAP) using a mask or nasal prongs (which act as a pneumatic splint providing the pressure to keep the nasopharyngeal air passages open) is now advised instead. Some therapy should be encouraged, because sleep apnea carries an increased risk of systemic and pulmonary hypertension, stroke, right heart failure, and polycythemia.

[edit] Excessive Daytime Sleepiness

Excessive daytime sleepiness is usually a symptom of chronic sleep loss, sleep apnea syndrome, narcolepsy, or such psychologic disorders as depression.

[edit] Narcolepsy

The full narcolepsy syndrome consists of a tetrad of symptoms: sleep attacks, cataplexy, sleep paralysis, and hypnagogic hallucinations (waking dreams). The sleep attacks are characterized by irresistible, brief (5 to 10 minute) sleep episodes that occur at times of decreased sensory stimulation. The patients may fall asleep at their desks, at the table, at the movies, in front of television, or in front of their house guests. They awake feeling quite refreshed. Some patients feel perpetually drowsy and have superimposed sudden sleep attacks of either REM or NREM type. Although sleep attacks may occur many times a day, there is usually a refractory period of a number of hours after each one.

Cataplexy is a sudden relaxation of muscle tone, usually precipitated by emotion, which causes the patient to slump, often falling on the floor but remaining conscious during this brief episode. Narcoleptics often learn to steel themselves against extremes of emotion (particularly laughing) to avoid these episodes. Some patients get only a partial weakness, exhibited by the sudden sagging of the jaw, face, and head, or their arms may drop to their sides. Rarely, a patient will experience slowing of speech or of all movements for a brief period.

Sleep paralysis usually occurs in the interval between sleep and wakening, often on awakening in the morning or after a sleep attack, when the patient finds that he or she is completely unable to move. Even though it may have occurred many times before, it is frightening, but seldom lasts longer than 60 seconds. Even a gentle touch terminates an attack.✢✢The fable of Sleeping Beauty may have been based on this syndrome, with the touch of prince's kiss unlocking her immobility. Mundane stimuli, however, are equally effective.

Hypnagogic hallucinations are vivid auditory or visual hallucinations or illusions that occur, like sleep paralysis, when the patient is in the state between wakefulness and sleep, or when coming out of a sleep attack. The patient is aware of what is going on around him or her but also experiences a vivid hallucination (e.g., the sight, sound, or voice of a long-dead parent) at the same time.

Although narcolepsy is classically a tetrad of symptoms, some patients also manifest symptoms of sleep drunkenness and disturbed nocturnal sleep. Narcoleptic symptoms appear to be normal components of REM sleep that occur at abnormal times. The sleep attacks are episodes of REM sleep in people who have the other components of the tetrad; but patients who have only sleep attacks may experience NREM sleep during the episodes. Both cataplexy and sleep paralysis appear to represent the motor inhibition that characterizes REM sleep. Hypnagogic hallucinations are vivid dreams as the person falls asleep. Unlike the memory of a dream, the dream is on while the person is awake and aware of his or her surroundings. These hallucinations are also different from the sleep fantasies that normally occur as a person falls asleep. Hypnopompic hallucinations††Hypnopompic hallucinations are the same thing as hypnagogic, except that they occur on waking up. represent a vivid dream such as would be normal during REM sleep but not when occurring in the drowsy stage as they do in this case. The night sleep of a narcoleptic patient is not normal but is disrupted, with frequent wakenings. In most cases, the first period of REM sleep has an unusually short latency (minutes rather than an hour or two).

Narcolepsy has to be differentiated from other causes of excessive sleepiness, such as idiopathic hypersomnia, hypothyroidism, depression, vertebrobasilar ischemia, and medication ingestions. The best diagnostic method is a careful history, but searching for the human leukocyte antigen (HLA) may be helpful because the prevalence of HLA-DR2, DQw1 in patient with narcolepsy is nearly 100%; thus if the patient lacks HLA-DR2, the diagnosis of narcolepsy may well be wrong. Pupillography is a research tool that may be used as an objective test for narcolepsy and is based on the facts that the pupil is large when the patient is alert, small when asleep, and intermediate when drowsy. It is an accurate way to evaluate a patient's ability to stay awake and has been used in evaluating sleepy drivers. Narcoleptic patients are a great risk on the highway because 77% report being drowsy when driving, 40% have fallen asleep at the wheel, and 16% have actually had accidents because of the narcolepsy.

After a definite diagnosis of narcolepsy has been made, the situation should be explained fully to the patient, to his or her family, and often to the patient's employer. The patient should not drive until therapy has been successful. Therapy may begin with methylphenidate, 10 mg tid, increased as required. The average patient takes 30 to 60 mg per day to control sleep attacks. Modafinil 200 to 400 mg/day, selegiline (up to 40 mg/day), and pemoline (37.5 mg po od) are alternatives. Amphetamines, once the mainstay of therapy, are rarely used now because of the problems of addiction, tolerance, and medicolegal complexities associated with their long-term use. Cataplexy, sleep paralysis, and hypnagogic hallucinations may not be helped by methylphenidate but may respond to imipramine or clomipramine (25 mg daily, increasing to 25 mg tid, if required). The selective serotonin reuptake inhibitor (SSRI) fluoxetine, 20 mg/day, is also effective against cataplexy.

[edit] PARASOMNIAS

[edit] Sleeptalking

Sleeptalking is the utterance of speech or sounds during sleep without subjective detailed awareness of the event. Such talking during REM sleep may represent the vocal expression of dream experiences, but it also occurs during transient arousals from non-REM sleep. In some cases, anxiety disorders or febrile illness are associated, and sleepwalking, obstructive sleep apnea syndrome, or REM sleep behavior disorder may also occur.

[edit] Sleepwalking

Sleepwalking is a sequence of complex behaviors during clouded consciousness that are seen mainly in prepubertal children and that tend to disappear spontaneously as they get older. It occurs during the first nocturnal periods of NREM sleep stages 3 or 4, with subsequent amnesia. It is hard to arouse the child during an episode, which may end with confused awakening or with a return to normal sleep. The person is able to perceive the world around to some extent because he walks around people and furniture. Sitting up in bed, perseverated simple movements, and complex automatic activities such as walking, going down stairs, and opening doors may occur. Attempts to restrain the subject usually lead to avoidance behavior.

Sleepwalking is seen less in adults than in children, among whom it may be associated with enuresis and sleep terrors. Although there is little evidence of psychologic disturbance in children who sleepwalk, there is some evidence that adults with this problem do have some underlying psychopathology.

Management of sleepwalking includes protection of the sleepwalker from injury, because he or she may wander into areas of danger or fall down stairs. A nightly dose of amitriptyline, clonazepam, or flurazepam may help sleepwalkers, although patients sometimes return to their sleepwalking patterns after 3 to 6 months despite the medication.

[edit] Sleep Terrors

A sleep terror is characterized by sudden awakening from sleep with intense anxiety, autonomic overstimulation, movement, and crying out. Despite the appearance of terror, the child has no memory for the event later, except for the feeling that something strange has just happened. The child with night terrors may also have enuresis or sleepwalking. Night terrors arise during stage 4 NREM sleep, often within the first hour. The child shows an impaired arousal response but a waking alpha EEG pattern, extreme motility, sleepwalking, and vocalization in the form of terrified screams or moaning. Pulse and respiratory rates increase but the episode is over within a minute or two. The child then has a feeling of intense fear and anxiety, respiratory restriction (hence the medieval image of a devil—an “incubus”—on the chest), and an overwhelming sensation of doom. Sleep terrors, like sleepwalking and other disorders of sleep, may be primarily disorders of arousal. Children with sleep terrors seldom require psychotherapy or medication.

[edit] Sleep-Wake Transition Disorders

Sleep starts may lead patients to complain either of difficulty falling asleep or of an intense body movement at sleep onset. These sudden, brief jerks at sleep onset, mainly affecting the legs or arms, are often associated with a subjective feeling of falling, a sensory flash, or a hypnagogic dream. They last less than a quarter of a second, mainly affect the legs, resemble the startle reaction of wakefulness, and occur in many people, usually during sleep onset. A positive family history is frequently found. Sleep starts represent a partial arousal response, are not associated with clinical or EEG abnormalities, and are of no pathologic significance.

Physiologic hypnic myoclonus is the condition of small, irregular twitches that occur normally in sleep and are of no significance. Virtually everyone has experienced these occasionally when just falling asleep. Brief attacks of dystonic, dyskinetic posturing during the night, lasting up to 2 minutes, have also been described and they respond well to carbamazepine.

[edit] Parasomnias Usually Associated With Rapid Eye Movement Sleep

Sleep paralysis is a dissociated REM sleep inhibitory process characterized by periods of flaccid paralysis of all but the respiratory and extraocular muscles with areflexia. Sleep paralysis occurs for minutes during the waking stage immediately preceding or succeeding sleep and is terminated by sleep or by sensory stimulation. The experience is frequently frightening, and some episodes are associated with hypnagogic hallucinations or dreamlike mentation. It may represent the tonelessness of normal REM sleep occurring in the conscious state. Cataplexy is the equivalent in the waking state. The syndrome may occur in isolation or as a component of the narcolepsy syndrome.

Dreams occur in both light NREM and REM sleep. A nightmare (or dream anxiety attack) is a normal but frightening dream, and the subject often has good recall of the episode initially if aroused from REM sleep. Nightmares are most common in childhood but may be induced in adults by the REM rebound that occurs after stopping a course of drugs such as benzodiazepines. The first step in management consists of determining the characteristics of the sleep disturbance. In adult cases, nightmares require only explanation and reassurance, but it is important to recognize that many medications used at bedtime may actually increase nightmares, l-dopa and propranolol for example. If treatment is required (when these drugs must be continued), then benzodiazepines in small doses may be helpful.

REM sleep behavior disorder is a striking behavior pattern related to REM sleep in which the patients (who are often older men) manifest vigorous and sometimes aggressive and dangerous activity associated with excessive limb or body jerking and dreams. They may jump from bed, damage furnishings, and injure (even murder) their bed partner or hurt themselves in the midst of an attack. It is important to remove objects and alter the room to minimize the danger of injury. Clonazepam, 0.5 mg at bedtime, usually suppresses the activity, but higher doses may be required.

Sleep-related painful erections are prolonged, painful erections that subside over minutes and often recur during the same night, usually during REM sleep periods. There are no associated deficits in sexual functioning, and erections during wakefulness are painless.

[edit] Other Parasomnias

Restless legs syndrome (RLS) is a common condition that particularly affects middle-aged people. In this disorder, the subject complains of a strong desire—almost a compulsion—to move the legs, often accompanied by paresthesias and dysesthesias in the legs; motor restlessness, worsening at rest and with temporary relief from activity; and worsening in the evening or at night. The clinical examination is usually normal, although the syndrome may also complicate pregnancy, peripheral sensory neuropathies from any cause, and iron-deficiency anemia. In most of the idiopathic cases there is a positive family history suggesting dominant inheritance. In addition to the conscious urge to move the legs, periodic limb movements are commonly associated during the lighter stages of NREM sleep. These are stereotyped patterns of flexion movements, always including dorsiflexion of the hallux, that occur repetitively once or twice per minute. The movements resemble akathisia, but their timing allows the differential. Vespers curse (lumbosacral and leg pain with leg cramps and fasciculations waking the patient from sleep) resembles RLS but occurs in patients with lumbar spinal stenosis and cardiac failure.

Therapy for RLS rests on the three pillars of benzodiazepines, opioids, and dopaminergic drugs. Levodopa-carbidopa (100 to 200 mg of levodopa) is the treatment of choice and is valuable for many patients. The controlled-release preparation reduces the tendency for a rebound increase in movements in the latter part of the night. Bromocriptine, 2.5 to 5 mg at bedtime, is almost as effective. Clonazepam, 0.5 mg at bedtime, is a reasonable initial therapy, and the dose can be increased to 2 mg if necessary. Clonidine, baclofen, carbamazepine, and pramipexole (0.125 mg at night, increasing slowly to 1 mg at bedtime if necessary) have also been used with some success. Methadone, 10 mg, codeine, 30 mg, or propoxyphene, 65 mg, may be effective but are preferably used only when other treatments have failed.

Nocturnal leg cramps are a common problem in the elderly, to whom they are a source of great misery. The calf pain is relieved only by standing up out of bed, but may still persist for some minutes. Prevention is easily accomplished, using small doses of quinine, 200 mg daily, dilantin, 200 mg at bedtime, and sometimes calcium lactate, 200 to 400 mg daily.

Primary enuresis refers to enuresis that continues after infancy, without any prolonged dry periods occurring. About one out of every six children are bedwetters at age 5, but up to 3% of healthy young adults still wet the bed occasionally. Primary enuresis is usually idiopathic, or may have a genetic basis in some cases, but sometimes results from organic diseases such as urethral obstruction, ectopic ureter, diverticulum of the anterior urethra, epispadias, or chronic urinary tract infection. Secondary enuresis is the recurrence of enuresis after a prolonged period of dryness and may be due to psychologic disturbance or to organic disease such as infection or diabetes.

Enuresis occurs in any stage of NREM sleep, most often in the first third of the night. The episode often begins in stage 4 sleep and is associated with a burst of rhythmic delta waves on the EEG, after which the sleep pattern switches to stage 2 or 1 and micturition occurs.

It is important to determine whether enuresis is primary or secondary. If primary, then reassurance and explanation are helpful, particularly because many other family members may have had and outgrown the same problem. One must look for organic problems in both primary and secondary cases. Careful attention must also be paid to psychologic factors. An understanding and empathetic approach must be taken with the children or they may see the encounter as a form of punishment. It is important to recognize not only psychologic cases of enuresis but the psychologic trauma and lowered self-image that can result. Parents often take a punitive attitude toward the child. Not only is this ineffective but it may augment the psychologic factors that worsen secondary enuresis. Therapy of primary enuresis begins with a reassuring explanation to the parents and the child based on an interview and examination. The child is advised to restrict fluids after supper, and on weekends and after school try to see how long he or she can hold urine in his or her full bladder. A parent should awaken the child late at night, usually when the parents are retiring, to have the child void again.

Imipramine, a tricyclic, is a moderately effective treatment for enuresis, but children are often made irritable by this drug. Its effect could be through decreasing stage 4 sleep or there may be a more direct effect on bladder innervation. An alternative method of therapy is the conditioning approach, using a mild electric shock pad that awakens the child at the first drop of urine. The Mozes detector has shown excellent results in clearing enuresis in 80% of children within 3 months. One has to be aware of the psychologic effect of this type of machine, and it has to be explained to the child with understanding and encouragement. Intranasal vasopressin (DDAVP) is a highly effective symptomatic remedy. Its remarkable ability to control enuresis suggests that the problem may sometimes be related to some failure of nocturnal secretion of this hormone by the posterior pituitary.

Sleep drunkenness is a parasomnia of adult life characterized by clouding of the sensorium with confusion and inappropriate impulsive behavior that occurs during an abnormally prolonged period of transition between the states of being asleep (commonly in a deep NREM sleep stage) and of being awake. Tiredness, impaired concentration, ataxia, headache, and drowsiness are also described.

Sleep bruxism is nocturnal grinding of the teeth, usually in the lighter stages of NREM sleep. It often runs in families and has no psychologic basis. Although dental malocclusion is thought to be associated, orthodontic treatment is expensive and generally useless as a remedy. A rubber mouthguard may be helpful.

Headbanging consists of rhythmic, rocking movements of the head and trunk that occur before or in the early stages of NREM sleep, usually in children.

Cluster headache (see Chapter 160 ) characteristically awakens the patient from sleep in the earliest hours of the morning during the first REM sleep period.

Infantile sleep apnea is the occurrence in infants of central or obstructive apneas during sleep. The clinical presentation includes noisy breathing during sleep, an episode of cessation of breathing during sleep characterized by pallor or cyanosis, and limpness, but rarely stiffness.

Nocturnal paroxysmal dystonia, sudden unexplained nocturnal death syndrome, sudden infant death syndrome, and primary snoring are other parasomnias described.

[edit] SLEEP DISORDERS ASSOCIATED WITH MEDICAL/PSYCHIATRIC DISORDERS

Sleep disturbances may also be associated with medical diseases such as sleeping sickness, chronic obstructive pulmonary disease, sleep-related gastroesophageal reflux, peptic ulcer disease, and fibrositis syndrome.

[edit] Medical Conditions Associated With Sleep

The list of medical conditions associated with sleep disturbance is very long, and only a few will be discussed here.

Myocardial infarction and episodes of angina commonly occur at night. There may be some relationship to the physiologic changes of REM sleep, but this has not been a consistent finding in all studies. It is now recognized, however, that sleep is not a quiet state of suspended animation, but a period with variable and often increased electrophysiologic, biochemical, physiologic, and psychologic activity—almost an “autonomic storm.” Such stresses may also induce cerebrovascular accidents.

Patients with duodenal ulcers secrete more gastric acid at night than normal subjects, primarily during REM sleep. This probably explains the common nocturnal pain and discomfort in such patients. Asthmatic attacks commonly occur at night, particularly in the early morning during stage 2 but rarely in stage 4.

Hypothyroid patients complain of excessive drowsiness, and sleep laboratory studies show that they mainly experience only the lighter stages of sleep. With replacement therapy, these patients regain a more normal sleep pattern. Pregnant women spend less time in the deeper stages of sleep. There may be increased sleeping and drowsiness during the first trimester of pregnancy, but increased wakening occurs as pregnancy continues. In encephalitis and dementing illnesses, reversal of the normal sleep pattern may occur, with sleeping during the day and alertness during the night.

Sleep disturbance in mental illness is well known. Depressed patients may oversleep, have difficulty getting to sleep because of superimposed anxiety, and experience early morning awakening. They take longer to get to sleep and spend twice as much time in light stages, often claiming they are not asleep at all. A disturbance in sleep patterns may predict deterioration in some mental illnesses; thus in schizophrenia acute episodes are often preceded by increasing insomnia, restlessness, and excessive rapid eye movements during REM sleep, suggesting overstimulation of the arousal system. In chronic organic brain syndromes, some patients have excessive REM sleep and others experience little.

Nocturnal seizures are common, especially in the epilepsies with focal origin. They usually occur in stage 2 NREM or in REM sleep periods. Both random and regular discharges may be recorded because of a decrease of inhibition, which leads to the jerking, twitching, or myoclonic movements that may be seen at the onset of sleep (very often in normal subjects as well) and may also initiate focal or generalized seizure activity. Vascular headaches commonly begin between 5 and 8 am. In fibrositis (fibromyalgia) syndrome, the muscle pains and headache are associated with disturbed sleep, and it has been suggested that the sleep disorder is primary.

[edit] ADDITIONAL READINGS

• ASDA Diagnostic Classification Steering Committee: The international classification of sleep disorders diagnostic and coding manual Rochester, Minn: American Sleep Disorders Association; 1990:
• C Guilleminault Sleep and its disorders in children. New York: Raven Press; 1987:
• DJ Kupfer, CF Reynolds: Management of insomnia. N Engl J Med 1997; 336:341 - 346.
• MW Mahowald S Chokroverty G Kader CH Schenck 'Sleep disorders: Continuum: Lifelong learning in neurology, Part A 1997; Vol 3:
• C Schapiro ABC of sleep disorders. London: British Medical Association; 1994: